Specific Process Knowledge/Thin film deposition/Deposition of Silicon Oxide/Deposition of SiO2 in E-Beam Evaporator Temescal-2
This page is written by Evgeniy Shkondin @DTU Nanolab if nothing else is stated.
All images and photos on this page belongs to DTU Nanolab.
The fabrication and characterization described below were conducted in 2023 by Patama Pholprasit and Evgeniy Shkondin, DTU Nanolab.
Evaporation of SiO2 in Temescal-2
This page describes e-beam evaporation method of SiO2 in Temescal (10-pocket). E-Beam Evaporator (10-pockets) - Temescal-2 allows deposition with elevated temperature and O2 gas bleed. This is ideal conditions of evaporation of oxides such as SiO2, TiO2, Al2O3 and ITO.
We highly recommend adding 5% O2 and maintaining a temperature of at least 200°C to achieve high-quality stoichiometric SiO2 films. Under these conditions, you can expect to produce optical films with smooth surfaces, excellent amorphous properties, and strong adhesion.
After prolonged usage, the responsible team must replace the target once it becomes black, as this indicates that the SiO2 pellets are starting to lose oxygen.
In these tests we evaporated SiO2 with 5% O2 and with and without temperature of 200 °C. Please be aware that evaporations requiring elevated temperatures should only be conducted using the 8-inch holder (as shown in the photo) with an adaptor tailored to the wafer size. Various accessories enable the use of the 8-inch wafer holder with a range of samples, from 8-inch wafers to small chips. NEVER attempt to use HULA with high-temperature processes, as they can potentially damage the magnetic components of HULA. If you are unsure, please consult the tool responsible for guidance.
SiO2 evaporates from source 9 or 10 in Temescal-2 using a graphite liner. Please write to metal@nanolab.dtu.dk at least a week in advance if you wish to request a material in a liner in pocket 9 or 10.
Photo of the 8-inch holder installed instead of HULA and used in Al2O3 and SiO2 evaporation tests.
SiO2 rise-soak procedure. Deposition rate: 1 Å/s.
Uniformity across 150 mm wafer
Results have been obtained for <100> 150 mm Si wafers with native oxide, based on ellipsometry study.
| Temperature (°C) / Thickness setpoint | Deposition rate (nm/s) | Tooling Factor | O2 Gas (%) | Average thickness (nm) | Minimum thickness (nm) | Maximum thickness (nm) | Standard deviation | Uniformity (%) |
|---|---|---|---|---|---|---|---|---|
| 200°C / 80 nm | 1 | 79 | 5 | 78.95 | 72.96 | 83.44 | 3.1268 | 6.6365 |
| room temperature / 80 nm | 1 | 79 | 5 | 85.43 | 80.36 | 89.02 | 2.5510 | 5.0737 |
Measured and fitted Psi and Delta functions of SiO2 thin film deposited on Si wafer using the e-beam evaporation method.
Thickness uniformity of SiO2 deposited on Si wafer using e-beam evaporation with 5% O2 gas and at 200°C. Thickness setpoint sat to 80 nm. Tooling factor - 79%.
Thickness uniformity of SiO2 deposited on Si wafer using e-beam evaporation with 5% O2 gas and at room temperature. Thickness setpoint sat to 80 nm. Tooling factor - 79%.
Optical functions
Results have been obtained for <100> 150 mm Si wafers with native oxide, based on ellipsometry study. Sellmeier model has been implemented for refractive index fitting.
Refractive index of 80 nm SiO2 deposited on silicon at room temperature and 200°C.
Deposition recordings
SiO2 evaporation monitoring. Deposition rate recording. Room Temperature, 5% O2, thickness setpoint 80 nm.
SiO2 evaporation monitoring. Gas flow recording. Room Temperature, 5% O2, thickness setpoint 80 nm.
SiO2 evaporation monitoring. Power recording. Room Temperature, 5% O2, thickness setpoint 80 nm.
SiO2 evaporation monitoring. Pressure recording. Room Temperature, 5% O2, thickness setpoint 80 nm.
SiO2 evaporation monitoring. Temperature recording. Room Temperature, 5% O2, thickness setpoint 80 nm.
SiO2 evaporation monitoring. Deposition rate recording. Room Temperature, 5% O2, thickness setpoint 80 nm.
SiO2 evaporation monitoring. Gas flow recording. Temperature 200°C, 5% O2, thickness setpoint 80 nm.
SiO2 evaporation monitoring. Power recording. Temperature 200°C, 5% O2, thickness setpoint 80 nm.
SiO2 evaporation monitoring. Pressure recording. Temperature 200°C, 5% O2, thickness setpoint 80 nm.
SiO2 evaporation monitoring. Temperature recording. Temperature 200°C, 5% O2, thickness setpoint 80 nm.
